Mining shovel horizontal compensator

ABSTRACT

A mining shovel including a base and a frame rotatably mounted above the base. An upper member is fixed to the frame, and a lower member is fixed to said base. The lower member is engaged with the upper member to transfer horizontal forces between the upper and lower members, wherein the upper member is rotatably slidable relative to the lower member, and the lower member is axially slidable relative to the upper member. A bushing is interposed between said upper and lower members.

CROSS REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the priority benefit of U.S. Provisional Patent Application No. 60/237,986 filed on Oct. 5, 2000.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not Applicable.

BACKGROUND OF THE INVENTION

[0003] This invention relates to mining shovels, and more particularly to a horizontal compensator for use in a mining shovel.

[0004] A conventional mining shovel generally includes a base supported by ground engaging tracks. The base rotatably supports a frame on which is mounted a housing for protecting mining shovel components, such as power generation equipment, electrical equipment, a dipper hoist, and controls. The frame also supports a dipper assembly and boom. The dipper assembly includes a dipper which engages the ground.

[0005] The frame rotates about a pintle which prevents horizontal and vertical movement of the frame relative to the base. In a known mining shovel, the pintle has one end fixed to the base, and an opposing end extending upwardly from the base into an aperture formed in the frame. Locknuts threadably engaging the pintle ends clamp the frame against the base through the rollers to counteract vertical forces exerted on the frame during the operation of the shovel. A bushing fixed to the radially outwardly facing surface of the pintle engages the frame to allow rotation of the frame relative to the pintle, and thus the base. Repair of the pintle, such as replacing the bushing, requires raising the frame above the base to gain access to the pintle.

[0006] Raising the frame relative to the base is time consuming, and requires an extended downtime for the mining shovel. A need exists for a mining shovel and pintle which does not require raising the mining shovel frame above the base to perform pintle maintenance.

SUMMARY OF INVENTION

[0007] The present invention provides a mining shovel including a base and a frame rotatably mounted above the base. An upper member is fixed to the frame, and a lower member is fixed to the base. The lower member is engaged with the upper member to transfer horizontal forces between the upper and lower members, wherein the upper member is rotatably slidable relative to the lower member, and the lower member is axially slidable relative to the upper member. A bushing is interposed between the upper and lower members.

[0008] A general objective of the present invention is to provide a horizontal compensator which is easy to maintain. This objective is accomplished by providing a horizontal compensator having a lower member slidable axially relative to the upper member, such that the lower member can be disengaged from the upper member without raising the frame for maintenance.

[0009] The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a perspective view of a mining shovel incorporating the present invention;

[0011]FIG. 2 is a perspective view of the base of FIG. 1 with the frame removed;

[0012]FIG. 3 is a perspective view of the horizontal compensator of FIG. 2; and

[0013]FIG. 4 is a cross sectional view of the horizontal compensator of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] A knee-action mining shovel 10, shown in FIG. 1, includes a base 12 supported by ground engaging tracks 14. The base 12 rotatably supports a frame 16 on which is mounted a housing 18 for protecting mining shovel components, such as power generation equipment, electrical equipment, dipper hoist, and controls. The frame 16 also supports a dipper assembly 22 and overhead boom 24. The dipper assembly 22 is pivotally connected to the frame 16, and supports a dipper 26 for engaging the ground. The overhead boom 24 extends over the dipper assembly 22, and supports hoist rope sheaves 25 which guide hoist ropes 28 attached to the dipper 26.

[0015] Referring to FIGS. 2 and 3, the base 12 includes a plate 30 (shown in FIG. 4) having an upper surface 34 which supports a ring gear 36. The ring gear 36 is fixed to the base 12, and engages a swing drive assembly mounted to the frame 16. The swing drive assembly 20 drives the frame 16 about the ring gear axis. Rollers 40 rotatably mounted to the frame 16 engage a top surface of the ring gear 36 to support the frame 16 above the base 12 for rotatable movement of the frame 16 relative to the base 12. Hook rollers 38 fixed to the frame 16 engage a lower surface of the ring gear 36 to counteract vertical forces exerted on the frame 16 during shovel operation.

[0016] A cylindrical horizontal compensator 42 counteracts horizontal forces exerted on the frame 16 during shovel operation, and has one end 44 fixed relative to the base 12 and an opposing end 46, rotatably independent of the one end 44, is fixed to the frame. The horizontal compensator 44 includes an upper cylindrical member 48 which is coaxial with a lower cylindrical member 50 and the ring gear 36. Advantageously, the upper and lower cylindrical members 48, 50 define a central channel 54 for electrical and pneumatic connections extending between the frame 16 and base 12 of the shovel 10.

[0017] A cylindrical bushing 52 interposed between the upper and lower cylindrical members 48, 50 allows the upper member 48 to rotate freely relative to the lower cylindrical member 50. Although a bushing 52 is disclosed herein, any friction reducing bearing, such as a roller bearing, and the like, can be used without departing from the scope of the present invention.

[0018] As shown in FIG. 4, the upper cylindrical member 48 has an inner diameter 49 defining an axis of rotation 57. A flange 56 formed at to an upper end 59 of the upper cylindrical member 48 abuts a lower surface 58 of the frame 16. Bolt holes 60 having an axis substantially perpendicular to the frame lower surface 58 are spaced circumferentially about the flange 56 and aligned with bolt holes 62 formed in the frame 16. Bolts 64 inserted through the aligned bolt holes 60, 62 fix the upper cylindrical member 48 relative to the frame 16. Ribs 61 are formed on the upper cylindrical member outer diameter 63 strengthen the upper cylindrical member 48. A second flange 65, shown in FIG. 4, can be provided to further strengthen the upper cylindrical member 48.

[0019] The lower cylindrical member 50 is fixed to a downwardly facing surface 72 of the base plate 30, and extends upwardly through an opening 53 in the base plate 30 to mate with the upper cylindrical member 48. An outer diameter 51 of the lower cylindrical member 48 slips into the inner diameter 49 of the upper cylindrical member 48 such that a portion 66 of the upper cylindrical member 48 overlaps a portion 68 of the lower cylindrical member 50. The lower cylindrical member is coaxial with the upper cylindrical member axis of rotation 57, and is rotatable relative to the upper cylindrical member 48 about the axis of rotation 57.

[0020] The lower cylindrical member 50 includes a flange 70 which abuts the downwardly facing surface 72 of the base plate 30. Bolt holes 74 having an axis substantially perpendicular to the base plate lower surface 72 are spaced circumferentially about the flange 70 and aligned with bolt holes 76 formed in the base plate 30. Bolts 78 inserted through the aligned bolt holes 74, 76 fix the lower cylindrical member 50 relative to the base 12. A recess 80 formed in the outer surface 82 of the overlapped portion 68 of the lower cylindrical member outer member 50 extends around the lower cylindrical outer surface diameter 51.

[0021] The bushing 52 is received in the recess 80, and has a radially outwardly facing surface 86 which engages the upper cylindrical member 48. The bushing radially outwardly facing surface 86 engages a radially inwardly facing surface 88 of the upper cylindrical member 48 to transfer horizontal forces between the upper cylindrical member 48 and the lower cylindrical member 50 while allowing slidable rotatable movement of the upper cylindrical member 48 relative to the lower cylindrical member 50. Preferably, the cylindrical bushing 52 is formed from two semi-cylindrical halves of a bushing material, such as bronze. The bushing halves are fixed to the lower cylindrical member 50 using methods known in the art, such as bolting and the like, to form the cylindrical bushing.

[0022] As discussed below, the horizontal compensator 42 is not required to counteract vertical forces resulting from the shovel operation, and can thus slide freely in the axial direction. Because the horizontal compensator 42 can slide in the axial direction, it can be disassembled without raising the frame 16 to provide access to the bushing 84 for maintenance. To disassemble the horizontal compensator, the lower cylindrical member 50 is unbolted from the base, and lowered away from the upper cylindrical member 48 to expose the bushing 52. The bushing halves can then be easily replaced using conventional tools.

[0023] Referring back to FIG. 1, the frame 16 supports the dipper assembly 22 and a gantry 89 which supports the boom 24. The dipper assembly 22 includes a stiff leg 90 pivotally mounted to the frame 16, and a dipper handle 92 pivotally connected to a stiff leg upper end 94 to provide the knee-action, and a crowd handle 94. The dipper handle 92 is a beam extending forwardly from the stiff leg 90 having a connecting end 96 pivotally connected to the stiff leg upper end 94, and a dipper end 98 supporting the dipper 26.

[0024] The dipper 26 is pivotally connected to the dipper end 98 of the dipper handle 92, such as well known in the art for mining shovels, for engaging the ground to extract minerals and the like. The dipper 26 is guided by the dipper handle 92, and is raised and lowered by the hoist ropes 28 suspended from the boom 24. Although pivotally connecting the dipper to the dipper handle is preferred, the dipper can also be rigidly connected to the handle without departing from the scope of the present invention.

[0025] The stiff leg 90 is pivoted relative to the frame 16 by the crowd handle 96 to move the dipper handle 92, and thus the dipper 26, in the forward and rearward directions. The crowd handle 96 has one end 100 pivotally connected to the stiff leg 90 proximal the stiff leg upper end 94, and a second end 102 extending rearwardly into the gantry 89 extending upwardly from the base 12. A crowd handle drive mechanism mounted in the gantry 89 drives the crowd handle 96 in a forwardly or rearwardly direction to pivot the stiff leg 90. Preferably, the crowd handle drive mechanism is a hydraulic cylinder 106 pivotally mounted to the gantry 89.

[0026] The boom 24 is an overhanging structure which is pin 108 connected at its lower end 110 to the gantry 88 above the stiff leg lower end 112, and has a distal end 114 extending forwardly over the dipper 26. The boom 24 is held in its angular position by upper suspension cables 116 having one end 118 attached to the boom distal end 114, and an opposing end 120 connected to the gantry 88.

[0027] While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims. 

We claim:
 1. A horizontal compensator for use in a mining shovel having a base supporting a frame, said frame being rotatable relative to said base, said horizontal compensator comprising: a lower member fixable to the base, and defining an axis of rotation about said lower member; an upper member mating with said lower member in an overlapping relation, said upper member being fixable to the frame and movable about said axis and along said axis; a friction reducing member interposed between said upper member and said lower member to reduce friction generated by relative movement of said upper member and said lower member, wherein a force acting in a radial direction against one of said upper member and said lower member is transmitted to the other of said upper member and said lower member, and a force acting in an axial direction against one of said upper member and said lower member is not transmitted to the other of said upper member and said lower member.
 2. The horizontal compensator as in claim 1, in which a first axial channel is formed in said upper member and a second axial channel is formed in said lower member, said first and second axial channels defining a passageway through the horizontal compensator.
 3. The horizontal compensator as in claim 1, in which said friction reducing member is a bushing.
 4. The horizontal compensator as in claim 1, in which said lower member includes a radially extending flange for fixing said lower member to the base.
 5. The horizontal compensator as in claim 1, in which said upper member includes a radially extending flange for fixing said upper member to the frame.
 6. The horizontal compensator as in claim 1, in which said upper member includes an opening coaxial with said axis, and mates with said lower member by receiving said lower member in said opening.
 7. A mining shovel comprising: a base; a frame rotatably mounted above said base; a horizontal compensator having an upper member fixed to said frame and a lower member fixed to said base, said upper and lower members being mounted in an overlapping relation to transfer horizontal forces between said upper and lower members, wherein said upper member is rotatably movable relative to said lower member, and said lower member is axially movable relative to said upper member.
 8. The mining shovel of claim 7, in which a friction reducing member is interposed between said upper member and said lower member to reduce friction generated by relative movement of said upper member and said lower member, wherein a force acting in a radial direction against one of said upper member and said lower member is transmitted to the other of said upper member and said lower member, and a force acting in an axial direction against one of said upper member and said lower member is not transmitted to the other of said upper member and said lower member.
 9. The mining shovel of claim 8, in which said friction reducing member is a bushing.
 10. The mining shovel of claim 7, in which said upper member includes a flange which is fixed to said frame.
 11. The mining shovel of claim 7, in which said lower member includes a flange which is fixed to said base.
 12. The mining shovel of claim 7, in which said flange engages a downwardly facing surface of a plate forming a part of said base, wherein said lower member axially moves out of the overlapping relation with said upper member when said lower member is detached from said base.
 13. The mining shovel of claim 7, in which said lower member extends through an opening in said base to mate with said upper member in an overlapping relation.
 14. The mining shovel of claim 7, in which a channel extends through said upper and lower members to provide a passageway between said frame and base.
 15. The mining shovel of claim 7, in which at least one hook is fixed relative to one of said frame and said base, and said hook is engageable with the other of said frame and said base to counteract vertical forces exerted on said frame.
 16. A horizontal compensator for use in a mining shovel having a base supporting a frame, said frame being rotatable relative to said base, said horizontal compensator comprising: a cylindrical lower member having an inner diameter and an outer diameter defining an axis of rotation about said lower member, said lower member being fixable to the base; a cylindrical upper member mating with said lower member in an overlapping relation, and having an inner diameter and an outer diameter coaxial with said axis, said upper member being fixable to the base and movable about said axis and along said axis; a friction reducing member interposed between said upper member and said lower member to reduce friction generated by relative movement of said upper member and said lower member, wherein a force acting in a radial direction against one of said upper member and said lower member is transmitted to the other of said upper member and said lower member, and a force acting in an axial direction against one of said upper member and said lower member is not transmitted to the other of said upper member and said lower member.
 17. The horizontal compensator as in claim 16, in which said friction reducing member is a bushing.
 18. The horizontal compensator as in claim 16, in which said lower member includes a radially extending flange for fixing said lower member to the base.
 19. The horizontal compensator as in claim 16, in which said upper member includes a radially extending flange for fixing said upper member to the frame.
 20. The horizontal compensator as in claim 16, in which said upper member inner diameter is greater than said lower member outer diameter, and mates with said lower member by receiving said lower member in said inner diameter.
 21. A method of disassembling a mining shovel horizontal compensator, wherein said horizontal compensator includes a lower member fixed relative to a base of the mining shovel and extending through a hole formed in the base and an upper member fixed relative to a frame of the mining shovel supported above the base, said lower member being in an overlapping relation with said upper member to counteract horizontal forces acting on the frame, said method comprising: detaching the lower member from the base; and lowering the lower member away from the upper member to expose overlapping portions of the upper member and lower member.
 22. The method as in claim 21, in which the lower member is bolted to the base, and detaching the lower member from the base includes unbolting the lower member from the base.
 23. The method as in claim 21, in which the horizontal compensator includes a friction reducing member interposed between the upper member and the lower member, and the method includes exposing the friction reducing member. 